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Fruit Flies at a Ripe Old Age

Life-span is partly controlled by the genetic makeup of an organism. In the nematode Caenorhabditis elegans, mutations in the daf pathway, which normally regulates an inactive hibernation-like life phase, can prolong life-span dramatically. The daf pathway is homologous to the insulin pathway of higher organisms, a tantalizing link to the ability of caloric restriction to increase rodent life-span. By mutating the genes in the insulin-like pathway of fruit flies, Tatar et al. and Clancy et al. generalize the participation of this pathway in life-span control. Mutation of the InR gene (homologous to the mammalian insulin receptor and the daf-2 gene) increased by 85%, and mutation of chico, an insulin receptor substrate, prolonged fly life-span by 52%. The insulin-like signaling pathway and its control of organismal metabolic activity is thus likely to be a general regulator of the rate of aging in a broad range of species. A news story by Strauss accompanies the articles.